Heat recovery system

ABSTRACT

A double pipe configuration for an HVAC system comprising an outer pipe, where the outer pipe is a hot gas exhaust pipe; an inner pipe positioned within the outer pipe, where the inner pipe is a cold air intake pipe, and where the cold air of the inner pipe is warmed by the hot exhaust of the outer pipe; and a plurality of radial fins to support the inner pipe within the outer pipe, where the radial fins redirect the heat within the outer pipe to warm the cold air within the inner pipe. The double pipe configuration may also be configured with a 90 degree elbow structure or a 45 degree bend structure to allow for the pipe to be positioned around objects.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a heat recovery system within an HVAC system wherein a smaller pipe receiving cold air is positioned within a larger pipe expelling hot gasses causing a heat exchange to warm the cold air within the inner pipe.

2. Description of Related Art

Heating, venting and air conditioning systems, commonly known as HVAC systems, are commonly used in buildings and homes to maintain indoor environmental comfort. The HVAC systems rely on complex principles of thermodynamics, fluid mechanics and heat transfer to make the systems operational. Typically within a home, the HVAC furnace is engineered to expel exhaust gasses to the outside. This wastes the energy to those hot gasses that could be used as a heat source. There are limited alternatives to allow a user to redirect those exhausted gasses in order to prevent the heat from being lost. It would be beneficial in the art to be able to redirect the heat in those gasses so that they serve to heat cold air rather than simply being wasted by being expelled from the system all together.

SUMMARY OF THE INVENTION

In view of the foregoing disadvantages inherent in the prior art, the general purpose of the present invention is to provide a double pipe configuration for an HVAC system, configured to include all of the advantages of the prior art, and to overcome the drawbacks inherent therein.

Accordingly, an object of the present invention is to provide a double pipe configuration for an HVAC system to redirect the heat in the exhaust gases that are typically expelled from the system back into the system to warm the cold air received from the outside. The object of the present invention is carried out by a double pipe configuration where an inner pipe positioned within an outer pipe, where the inner pipe receives cold air from the outside. The cold air is warmed by heat exchange caused by the hot gases expelled through the outer pipe.

To achieve the above objects, in an aspect of the present invention, a double pipe configuration for an HVAC system is described comprising an outer pipe, where the outer pipe is a hot gas exhaust pipe; an inner pipe positioned within the outer pipe, where the inner pipe is a cold air intake pipe, and where the cold air of inner pipe is warmed by the heat exchange with the hot exhaust of the outer pipe; and a plurality of radial fins to support the inner pipe within the outer pipe. The radial fins increase heat exchange between the inner pipe and outer pipe to warm the cold air within the inner pipe. The double pipe configuration may also be configured as a 90 degree elbow structure or a 45 degree bend structure to allow for the pipe to be positioned around objects.

These together with other aspects of the present invention, along with the various features of novelty that characterize the present invention, are pointed out with particularity in the claims annexed hereto and form a part of this present invention. For a better understanding of the present invention, its operating advantages, and the specific objects attained by its uses, reference should be made to the accompanying drawings and descriptive matter in which there are illustrated exemplary embodiments of the present invention.

BRIEF DESCRIPTION OF THE DRAWINGS

The advantages and features of the present invention will become better understood with reference to the following detailed description and claims taken in conjunction with the accompanying drawings, wherein like elements are identified with like symbols, and in which:

FIG. 1A depicts a double pipe configuration in accordance with the present invention with dimensions A, B and C.

FIG. 1B depicts an end view of the double pipe configuration in accordance with an exemplary embodiment of the present invention;

FIG. 2A depicts a side view of a double pipe configuration with an elbow joint;

FIG. 2B depicts a front view of the double pipe configuration with the elbow joint;

FIG. 3 depicts a side view of a double pipe configuration for a 45 degree bend in accordance with an exemplary embodiment of the present invention;

FIG. 4(A) depicts a side view of a furnace header and a front view (B) in accordance with an exemplary embodiment of the present invention;

FIG. 5(A) depicts a side view of an outside header in accordance with an exemplary embodiment of the present invention;

FIG. 5(B) depicts a front view of the outside header in accordance with an exemplary embodiment of the present invention;

FIG. 6A depicts a perspective view of a radial fin from a front view (A);

FIG. 6B depicts a side view of the radial fin in accordance with an exemplary embodiment of the present invention;

FIG. 7A depicts a perspective view of an internal fin from a front view;

FIG. 7B depicts a side view of the internal fin in accordance with an exemplary embodiment of the present invention; and

FIG. 8A depicts an alternative embodiment of an internal fin with a flange in accordance with the present invention.

FIG. 8B depicts a corrugated embodiment of an internal fin accordance with an exemplary embodiment of the present invention.

Like reference numerals refer to like parts throughout the description of several views of the drawings.

DETAILED DESCRIPTION OF THE DRAWINGS

The present invention relates to a heat recovery system within an HVAC system wherein a smaller pipe receiving cold air is positioned within a larger pipe expelling hot gasses to warm the cold air within the internal pipe. The cold air intake pipe is enclosed and warmed by heat exchange with the outer exhaust pipe containing warmer gas and centered by three or more radial fins. The pipes carrying cold air from the outside are slip fit together with the pipe closer to the outside fitted inside the pipe nearer to the furnace. The outer pipe which carries the hot exhaust to the outdoors is also slip fit, but with the pipe closer to the furnace within the pipe closer to the outside. The system is entirely passive utilizing the furnace's intake/exhaust blower for activation.

Turning now descriptively to the drawings, referring to FIG. 1, a double pipe configuration 10 is shown from a side view 1(A) in accordance with an exemplary embodiment of the present invention. The double pipe configuration 10 includes an outer pipe 12 that surrounds an inner pipe 14. The outer pipe 12 is a hot gas exhaust pipe that carries hot exhaust outdoors, and the inner pipe 14 is a cold air intake pipe. The inner pipe 14 is supported within the outer pipe 12 with a set of radial fins 16. Additionally, a set of internal fins 18 are positioned within the inner pipe 14. The internal fins 18 are especially useful when the run from the furnace to the outside is short. The outer pipe 12 may vary in diameter in a range such as 3 to 4½ inches, and the inner pipe 14 may vary in diameter in a range such as 2 to 3 inches. In the preferred embodiment, the diameter of the outer pipe 12 is 1.5 times greater than the diameter of the inner pipe 14. The pipes and fins 12, 14 may be made from copper, galvanized steel or aluminum.

An end view is shown of the double pipe configuration 10 in FIG. 1(B) where the inner pipe 14 is illustrated inside the outer pipe 12. The radial fins 16 are illustrated in supportive positions around the inner pipe 14. The radial fins 16 assist in transferring heat from within the outer pipe 12 to heat the cold air within the inner pipe 14. Illustrated in two pieces, the separate pieces of the double pipe configuration 10 are connected together with slip fit connections for a tight and fluid transition.

Referring now to FIG. 2(A), an elbow structured double pipe configuration 40 is shown from a side view in accordance with an exemplary embodiment of the present invention. The elbow structure double pipe configuration 40 includes an outer pipe top extension 42 and an outer pipe bottom extension 46 that meet at a 90 degree joint 44. The 90 degree joint 44 allows the elbow structured double pipe configuration 40 to bend and be positioned around objects. The inner pipe 50 also bends with the outer pipe 42, 44, 46. The inner pipe 50 is suspended with a plurality of radial fins 60 to maintain the positioning of the inner pipe 50 within the outer pipe 42, 44, 46. A set of radial fins 60 support the inner pipe 50 along the outer pipe top extension 42 and along the outer pipe bottom extension 46. A front view of the elbow structured double pipe configuration is illustrated in FIG. 2(B). The radial fins 60 are better illustrated in a radial configuration around the inner pipe 50 to support the inner pipe 50 within the outer pipe 42.

Referring to FIG. 3, a side view of a double pipe configuration 150 for a 45 degree bend is shown in accordance with an exemplary embodiment of the present invention. The 45 degree bend double pipe configuration 150 includes an outer pipe angular extension 152 that meets with an outer pipe extension 156 at an outer pipe bend 154. The inner pipe 160 follows the 45 degree angular bend of the outer pipe 152, 154, 156. The 45 degree bend double pipe confirmation 150 also includes the plurality of radial fins 158, as previously described in FIG. 1. The 45 degree bend double pipe configuration 150 provides an additional angled double pipe that provides the exact in between for a straight double pipe configuration as illustrated in FIG. 1 and the 90 degree double pipe configuration illustrated in FIG. 2.

Referring now to FIG. 4(A), a side view of a furnace header 100 is shown in accordance with an exemplary embodiment of the present invention. The furnace header 100 includes an outer pipe 102 and in inner pipe 104, with a set of radial fins 106. During use, the hot exhaust air goes into pipe 108 in the direction indicated at W. The hot exhaust air circulates through the outer pipe 102 thereby warming air transferring to the furnace X through inner pipe 104. The furnace header 100 is attached near the furnace of the HVAC system. FIG. 4(B) illustrates the furnace header 100 from a front view wherein pipe 108 is facing forward.

In FIG. 5(A) a side view of an outside header 120 is shown. The outside header 120 is a portion of the HVAC system that is setup to receive air from outside. The cold air is received into the inner pipe 124 in the direction indicated at Y. Hot air is released from the system at pipe 128 indicated at Z after being used to warm the cold air in the inner pipe 124 and circulates through outer pipe 122. FIG. 5B illustrates a front view of the outside header 120 wherein the pipe 128 is facing forward.

Referring now to FIG. 6 a front view of the radial fin 16 is illustrated in 6(A) and the side view of the radial fin 16 is illustrated in 6(B). The fin 16 includes radial arms 11 that assist in supporting the inner pipe within the outer pipe. The radial arms 11 each include a support 13 that rests between the radial arms 11 and the surrounding pipe. The radial arms 11 each include a flange 15 that assists in heat recapture. A side view of the radial fin 16 is illustrated in FIG. 6(B).

Referring to FIG. 7 a front view of the internal fin 18 is shown in FIG. 7(A) and a side view is shown in FIG. 7(B). Similar to the radial fins 16, the internal fins 18 include a set of arms 21, where each arm 21 includes a support 23 to support the radial fin 18 within the inner pipe. The radial fins 16 and the internal fins 18 not only conduct heat from the exhaust to the inner pipe 14 and the walls of the inner pipe 14 which are heated by hot air flow within the outer pipe 12 to warm the incoming cold air, but the flanges 15, 25 may be added to create turbulence further assisting in warming.

Finally, referring to FIG. 8, alternative embodiments of the fins are illustrated. FIG. 8(A) illustrates a fin 80 with an arm 82 and an extended flange 80. Alternatively, FIG. 8(B) illustrates a fin 90 with an arm 92 and a support 94. The arm 92 is corrugated for greater heat capture.

During use, the double pipe configuration reclaims the heat from the exhaust gasses of modern energy efficient furnaces expelled to the outside. The system is passive utilizing the furnaces intake/exhaust blower. The heat recovered can boost the efficiency of a furnace without additional fans or blowers and a little or no difference in cost. The inner pipes carrying the cold air from the outside are slip fit together with the pipe closer to the outside fitted inside the one nearer the furnace. The radial fins increase the transfer of heat to the cold air. For short runs or to further increase the warming of the outside air, additional radial fins may be added to the inner pipe, or the cold air intake pipe. The outer pipe is also slip fit, but with the pipe closer to the furnace inside the pipe closer to the outside. The double pipe configuration replaces the two PVC intake and exhaust pipes. The elbow structured double pipe configuration and 45 degree structured double pipe configurations are premade to allow positioning around objects, and the 45 degree structured double pipe configuration may better reduce drag. The double pipe may be sealed by screws and/or metal backed tape. If condensation inside the exhaust pipe becomes a problem a simple valve at the furnace header connected to the humidifier return line can be installed.

The foregoing descriptions of specific embodiments of the present invention have been presented for purposes of illustration and description. They are not intended to be exhaustive or to limit the invention to the precise forms disclosed, and obviously many modifications and variations are possible in light of the above teaching. The exemplary embodiment was chosen and described in order to best explain the principles of the invention and its practical application, to thereby enable others skilled in the art to best utilize the invention and various embodiments with various modifications as are suited to the particular use contemplated. 

What is claimed is:
 1. A double pipe configuration for an HVAC system comprising: an outer pipe, where the outer pipe is a hot gas exhaust pipe; an inner pipe positioned within the outer pipe, where the inner pipe is a cold air intake pipe, and where the cold air of inner pipe is warmed by the hot exhaust of the outer pipe; and a plurality of radial fins to support the inner pipe within the outer pipe, where the radial fins redirect the heat within the outer pipe to warm the cold air within the inner pipe.
 2. The double pipe configuration for an HVAC system according to claim 1, where the outer pipe is 3 inches in diameter and the inner pipe is 2 inches.
 3. The double pipe configuration for an HVAC system according to claim 1, where the inner pipe includes a set of internal fins.
 4. The double pipe configuration for an HVAC system according to claim 1, where individual double pipe configurations are slip fit to each other.
 5. The double pipe configuration for an HVAC system according to claim 1, where the inner pipe and the outer pipe are made from one of at least copper, galvanized steel and aluminum.
 6. The double pipe configuration for an HVAC system according to claim 1, where the double pipe configuration is a 90 degree elbow structure to allow the system to be positioned around obstacles.
 7. The double pipe configuration for an HVAC system according to claim 1, where the double pipe configuration is a 45 degree bend structure to allow the system to be positioned around obstacles. 